Dental mallet



y I I D. REITER 2,376,187

DENTAL MALLET Filed Nov. '13, 1944 Patented May 15, 1945 This invention pertains toja dental mallet and particularly to an automatic type thereof.

An object of the invention is the provision, in a dental mallet, of a simple arrangement of relatively few component parts having a minimum number of wearing'surfaces and being positive.

in action.

Another object of the invention is the provision, in a dental mallet, of means capable'of adjustment a nd controlling the release of a hammer so as to gauge the degree of forces-in a hammer blow.

A, further object of the'invention is to provide adental mallet which may be adjustable'so as to controlthe stroke of a tool as well asthe force J DIied to thetool.

An added object of the invention is to provide a mallet of the automatic type which is of such design as to be easy to operate because it-may be manipulated quite effectively-by one hand, ineirpensive to manufacture, because of relatively {few parts v and easily assembled or disassembled for general repair, inspectionor replacement o' f 'parts. vThe above and numerous other objects of 't'hje invention will become apparent from. the j succeeding description considered together with the a co a yin -dr w whi rdise s i l vf views; an exemplification ofythe invention and wherein: h i

vFigurefl 1,-is a lonsilmdi aIJse tionaI yiew of a de al mallet emb dyi a fo o th presen invention. a

Figure 2 is a partial longitudinal sectional View corresponding to Figure 1 ,and illustrating some of the elementsoflthe mallet in an it abnormal relationship, I

Figure3 is a transverse sectional view taken along the lines ,3,-3 vof Figure.1,,lookinginthe direction: of the arrows.

Figure. 4 is an elevational view showing a modification of one. of the components, of the mallet. Referring now indetailto the drawing, wherein likereference characters refer tolike parts, the

numeral I is employed to indicate, in a somewhat general manner a mallet of an 'automaltic type and which, more pftenherein throughout, may be referred toas a dental inallet, but ,it will be understood that, the malletmay be used generally for any type. of surgery wherein an instrument of the v class described maybe, employed advantageouily 1 ra v on b n or. benrs mc r The mallet, comprisesa main barrel or outer sheathing 2 extending longitudinally of the instrument for substantially itsentire length and beingformed preferably as a hollow, round cylinder open at both ends to function asa casing-or a foundation. 1 Removably-securedto one end; of the barrel is a guide ;member 3 threadedly associated with" thebarrel to form adefinite interlock therebetween. The; guide member has; extending axially,thereof,-an opening 3 through which extendsashank 4 of a plunger element 5.

The plunger is arrangedto-move axially or longitudinally of-the-mallet within certain predetermined limits and accordingly, has asgan-inner 'end thereof a head,- anvil or blow or impact receiving enlargement 6 disposed within the barrel. Interposed between the anvil and guide member is a resilient element characterized 'by a coilor helical spring 1 acting longitudinally of =themal1et to maintain theplunger in a normal'or retracted position as-illustrated. So as to'limittheinward movement of the plunger the ou'ter'or freeend thereof is provided With'a'chu'ck element 8 which normally bears-against an associated end of the guide member. The chuck element may be so adjusted longitudinally of the plunger as to govern the effective travel of the plunger, that is to say,by manipulating the chuck so that it is disposed closer or farther away from the anvil'the compressive action ofthe resilient element can be effected to thereby shorten or lengthen the effectivestroke of the plunger. The limits of travelof the plunger is of course the free and solid heights of the-resilient-element- 'and'fche chuck may be so"manipulated as to effect a plunger stroke equal to any fraction or whole of the range of resilient element action. Extending from the outer or freeend of the plunge'ris a tool 9 whichis depicted as a chisel butyhowever, may equally be a bit, elevator or any such suitable implement employed in the art of surgery and ada ted to receiveimpacts or blows. The tool or implement 9 is removably retained associated with theplunger by meansof the chuck and, accordingly, any forces imparted .to "the plunger will be reflected immediately in the tool. Disposed within the sheathing intermediate the ends thereofis a hammer l0 alsoof cylindrical remand arranged 'to slide' within thebarrel awayiromand toward the plunger anvil. Normally, the hammer bears against, the anvil from which position it can bedrawn along the barrel poisedin-spaced relation to the plunger so that upon release thereof, an impact or blowcan be imparted to the plunger anvil'to' drivevthe tool in a direction outwardly of themallet. ;The extremity of the sheathing removed from the guide means is provided with exterior threads with which interior threads of a cap or closing memher II are interlocked. Interposed between the cap and hammer and in intimate contact therewith is a resilient element or coil or helical spring I2 forming a power means resting against the hammer for urging the latter away from the cap or toward the plunger. The threads presenting an interlock between the barrel and cap also present an adjusting means whereby the resistive value of the spring I 2 can be definitely established. That is to say, as the cap is run out on the sheathing away from the normal position of the hammer the compressive value of the resilient element for a given stroke will be lessened to result in a lighter blow being imparted to the anvil and conversely the closer the cap is to the anvil the greater the degree of forces will be built up in the resilient element to intensify the hammer blows.

Means has been incorporated in the mallet for moving the hammer away from its normal position and as exemplary of such a means the hammer is provided with a circumambient, outwardly facing raceway l3 which is in the nature of a channeled relief and need only extend around the hammer for a relatively short distance if so desired and for all purposes and intent may be formed by taking a straight out or kerf across the face of the hammer intermediate the length thereof. The raceway is, however, preferred because it is easier and more economical to form in the hammer. In Figure 4 of the drawing there is disclosed an elevational view of a hammer having a straight out or kerf indicated as I3 and this design or construction may be employed in lieu of the continuous circumambient raceway. Leading axially r inwardly of the hammer from the raceway or kerf is a cross bore I4 extending to the axis of the hammer where it communicates with an axial bore IS, the latter of which extends from the cross bore to the spring element adjacent end of the hammer.

Movably associated with the barrel is a sleeve I6 of cylindrical formation surrounding the sheathin and having one portion l6" thereof in sliding engagement with the barrel to guide the sleeve in a definite fixed path throughout its range of movement axially of the mallet. Outstanding in opposite directions of the sleeve intermediate the length thereof is a pair of wings I! which function as finger grips or pieces to assist in operating the mallet. Any means such as the illustrated stop I8 may be removably associated with the barrel to limit the travel of the sleeve in one direction or toward the plunger associated extremity of the barrel. Formed on one of the finger grips is a housing I9 having an opening normal or perpendicular to the axis of the hammer or in alignment with a normally positioned cross bore and as such has one or the outer end thereof closed by means of an adjustable or rotatable element or set screw 20. Disposed within the housing and having one end bearing against a contiguous extremity of a set screw is a coil spring .or deformable element 22 which tends to urge a retractible means or pin 23 outwardly of the housing or inwardly of the mallet toward the longitudinal axis thereof. The pin has a cylindrical butt portion 24 normally disposed within the raceway or kerf of the hammer and because of the formation or presence of the overlying shoulder or shoulders 25 at the upper limits of the raceway or kerf a definite or positive interlock is formed between the leeve and hammer. It is deemed well to here state that the barrel is provided with a slot or elongated opening 21 of sufflcient width to accommodate the butt end of the pin or retractible means and by reason of this accommodating guideway 21 the sleeve is prevented from rotating relative to the barrel and is maintained in a definite, fixed path. Also the set screw is made adjustable so that a definite value can be established in the deformable element 22 thereby controlling the degree of force necessary to retract or urge the pin back into the housing. It will be obvious to one skilled in the art that the greater degree of forces required to disengage the pin from the hammer will result in a greater degree of forces being built up in the resilient element or hammer power means. Spaced a predetermined distance above the finger grips is an abutment or ledge 28 circular in formation and outstanding from the barrel as an integral part thereof. Th sleeve is continued away from the finger grips as a slightly enlarged portion 29 in radial spaced relation to the barrel and normally overlapping the barrel ledge. Disposed within this enlarged sleeve portion is a coil spring 30 which reacts axially of the mallet against the ledge and sleeve so that after a tripping action of the pin-hammer interlock the sleeve may be returned through the action of the coil spring 30 to its normal position as illustrated most clearly in Figure 1 of the drawing.

As previously indicated, the pin-hammer interlock is tripped to release an elevated hammer and impart a blow or impact to the plunger, and

. toward the fulfillment of the above the pin is provided with a nib, nipple or extension 3| which extends through the cross bore into the axial bore. The extension or nipple is of lesser cross sectional area than the pin butt and has a free end tapered or rounded as at 32 which normally occupies a position within the axial bore. Adjustably associated with and carried by the cap is a rod or pin tripping device 34 of such cross sectional area to be neatly accommodated by the hammer axial bore so as to function additionally as a guiding means for the hammer throughout its range of movement axially 0f the mallet. An outer end 01 the bar has secured firmly thereto a thumb rest, piece or saddle 35 arranged to bear against the base of a thumb of an operator. The saddle is also employed as a means for rotating the bar relative to the cap to change or alter the effective length of the bar within the barrel. The opposite end of the bar terminates short of the pin nib so as to be normally spaced therefrom and is formed as a tapered or rounded extremity 36. The hammer, in addition, is provided with an outwardly facing longitudinal groove or recess 31 elongated along the length of the hammer from the area of the cross bore and circumambient raceway or kerf toward the spring adjacent end of the hammer. The recess 31 is in radial alignment with the slot but is narrower than the slot and is, therefore, of a width slightly greater than the diameter of the pin extension so that during certain operating conditions hereinafter explained the pin extension will b uidingly received by the recess 31. This relationship between the pin extension and longitudinal groove prevents a rotative action of the hammer throughout its entire range of axial movement and, accordingly, at all times maintains the cross bore and raceway or kerf in position to receive the pin extension and pin butt respectively when the components of the mallet are permitted to return to normal position as illustrated in Figure 1 of the drawing. Where the longitudinal groove merges. or opens into the cross bore an arcuate or convexly curved surface 38 is provided, thereby presenting a skidway leading from the cross bore to the longitudinal groove. as the "sleeve is urged toward the thumb piece or rest, the pin butt, being interlocked with the hammershoulder 25, causes the hammer to raise away from the plunger and this action continues until the bar extremity 36 engages-the pin extension free end 32 to thereby urge the pin to Accordingly,

3. In anautomatic mallet, the combination of, abarrel, a hammer in said barrel arranged to impart a blow to a plunger, a sleeve surrounding said barrel and arranged to move axially thereof,

a slot in said barrel, housing means carried by.

said sleeve, spring means within said'housing,

bemoved into the housing a distance suiilcientv r to trip the pin-hammer interlock, as most clearly illustrated in Figure 2 of the drawing. As the pin butt is urged from beneath the hammer shoulder and the pin extension at the same time enters the longitudinal recess over the skidway 88 the hammer, through the medium of the forces built up in the coil spring I2,is dispatched on its way to imparta blow or impact on the plunger.

By relieving the pressurelon the finger grips the coil spring 30 will return. the sleeve back to abutting relation with the stop l8 at which time the spring 22 will urge the pin once more into underlying supporting relation with the hammer shoulder 25.

From the above it will be noted that various changes and alterations may. be made to'the illustrated and described construction without transversely movable means bearing against said spring means and extending out of said housing through said slot, said transversely movable -means extending into said hammer to form an interlock therebetween for moving said hammer in one direction axially of said' barrel, a cap as'-' sociated'with one end of said barrel, a coil spring acting between said cap and hammer, and stem means carried by said cap and extending axially of and into said'hammer, saidstem means being arranged to disengage said transversely movable means from said hammer'after a predetermined movement of said hammer toward said cap.

4. In an automatic mallet, the combination of.

a barrel, a hammer in said barrel arranged to impart a blow to a plunger, a sleeve surrounding said'barrel and arranged to move axially therea of, housing means carriedby said sleeve, spring means within said housing, transversely movable means having respective ends bearing against said spring means and interlocked with said hammer,

' -a cap associated with one end of said barrel, a

departing from within the spirit of the invention and scope of. the appended claims.

Iclaim: Y 1' 1, In an automatic mallet, the combination of. a sheathing, a reciprocating plunger slidably associatedwith one end of said sheathing, a hammer in said sheathing normally bearing against said sleeve and extending through said sheathing,

said transversely, movable means arranged to in-.

coil springacting between said cap and hammer, and stem means carried by said cap and extending axially of and into said hammer; said stemmeans being adjustable axially of said barrel and arranged to disengage said transversely movable means from said hammer after a presaid plunger, :a sleeve surrounding said sheathing and arranged to'move relative thereto within certain predetermined limits, spring means acting between said sheathing and sleeve' for normally holding the latter in one position, resiliently actuated transversely movable means carriedfby terlock with said hammer, cap means closing the other end of said sheathing, a spring bearing against said cap and hammer, and means carried by said capmeans and extending into said hammer, said last named means being in' alignment with but normally spaced from an end of said transversely'movable' means so as to negative said interlockbetween said transversely movable. means and. hammer after a predetermined movement of said sleeve.

2. In an automatic mallet, the combination of, a barrel, a reciprocating plunger slidably associated with one end of said barrel, a hammer in said barrel arranged to impart a blow to said plunger, a shoulder formed on said hammer, a sleeve surroundingsaid barrel and arranged to move axially thereof, a slot in said barrel, transversely movable means carried by said sleeve and extending through said slot, said transversely movable means extending into said hammer and normally underlying said shoulder .to form an interlock therebetween for moving said hammer away from said'plunger, a capassociated with the other end ofsaid barrel, spring means acting between said cap and hammer, and stem; means associated with said cap and extending into said hammer, said stem means being adapted to disengage said transversely movable means from said hammer after a predetermined travel of said hammer away from said plunger.

determined movement of said hammer toward said cap.

5. In an automatic mallet, the combination'of, a barrel, a hammer in said barrel adapted to impart a blow to a plunger, an axial bore in said hammer, a cross bore in said hammer communicating with said axial bore, a sleeve arranged to move axially of said barrel, a housing carried pressive movement of said spring means.

6. In an automatic mallet, the combination of, a barrel, a hammer in said barrel adapted to impart a blow to said plunger, an axial bore in said hammer, an outwardly facing groove in said hammer parallel with said axial bore, a cross bore,

adjacent one end of said groove and communicating with said axial bore, a sleeve arranged t move axially of said barrel, a housing carried by said sleeve a resiliently urged pin extending out of said housing into said cross bore to thereby form an interlock between said sleeve and hammer for moving the latter in one direction axially of saidbarrel, spring means urging saidhammer axially of said barrel, and meansadjustably associated with said barrel and extending into said axial bore to have an end thereof normally spaced from said cross bore; the end said spring-means.

of said last named'means being arranged to urge i said pin out of said cross bore into said groove after a predetermined compressive movement of DAVID REITER.- 1 

